1. Field of the Invention
The present invention relates to the structure of above-ground swimming pools and the methods in which above-ground swimming pools are installed. More particularly, the present invention relates to the preparation of the grounds on which an above-ground pool is placed when installed.
2. Prior Art Statement
The prior art is replete with different types and styles of above-ground swimming pools. Above-ground swimming pools are pools that contain a framework that is assembled on top of the ground or another exterior surface. A waterproof liner is then placed in the framework and the liner is filled with water to create the pool.
Above-ground swimming pools are popular for many reasons. One reason above-ground pools are so popular is that above-ground pools are temporary and do not require the excavation of land, as would a permanent in-ground pool. Accordingly, a person can assemble an above-ground pool and keep it for one summer season, or for many years. Once the pool is no longer desired, it can easily be dismantled and stored.
Another reason above-ground pools are so popular is that they are very inexpensive as compared to the cost of permanent in-ground pools. For many homeowners who want a private pool but cannot afford a permanent in-ground pool, above-ground pools are the only option.
A third reason above-ground pools are so poplar is that they do not require any permanently built structure. As such, many municipalities do not require building permits for the installation of above-ground pools. Furthermore, many homeowners are prevented from building in-ground pools because of local zoning ordinances. Such homeowners also have no choice but to use an above-ground pool, if they desire their own private pool.
Since above-ground pools are popular among a wide range of people, above-ground pools are manufactured in a wide range of shapes, styles and depths to accommodates the needs and tastes of that wide range of people. However, regardless of the shape, style or depth of the pool, the basic construction of an above-ground pool remains the same. Traditional above-ground pools have a framework that supports a continuous vertical wall. It is this continuous vertical wall that serves as the periphery of the above-ground pool. Once the continuous vertical wall is in place, the interior of the area that is surrounded by the vertical wall is lined with a pool liner. The pool liner is draped across the area defined by the continuous vertical wall so that the pool liner covers the ground within the limits of the vertical wall and covers the interior surface of the peripheral wall. It is the pool liner that retains water within the space defined by the continuous vertical wall. The continuous vertical wall merely supports the edges of the pool liner. Once the liner is secured in place, the pool liner is filled with water and the pool is complete.
There are disadvantages to the design of above-ground pools. Pool liners are thin and flexible. If the liner tears at any point, water will leak from the pool until the water level in the pool reaches the level of the tear. Pool liners are flat sections of waterproof material that are draped across an above-ground pool. Since the pool liner is manufactured as a flat sheet, the pool liner often buckles and folds as is conforms to the shape of the pool. As people in the pool walk around the pool, or as the pool is cleaned with various equipment, these folds wear from contact and often begin to leak over time. As such, the pool must be periodically drained and the pool liner replaced or repaired.
One factor that greatly effects the wearing of pool liners, is the condition of the ground surface below the pool liner. If an above-ground pool is constructed over hard concrete, the pool liner wears rapidly as the pool liner chafes against the concrete. If the above-ground pools is constructed over rocky soil or rooted soil, the rocks and roots can puncture the pool liner or create bulges on the pool liner that wear quickly. Even above-ground pools constructed over rock free soil may encounter rocks over time. As the weight of a filled pool presses upon the ground, the soil compacts. Rocks buried below the ground may then become present on the surface of the ground, where the rock contacts the pool liner. Lastly, if an above-ground pool is constructed over a wooden deck, the liner bulges in the spaces between the planks. The bulges eventually tear, thereby requiring that the pool liner be replaced.
According to the manufacturer's instructions, one of the best surfaces to construct an above-ground pool on is soft granular sand. The sand supports the pool liner at all points and evenly distributes stresses experienced by the pool liner. It is for this reason that many people place sand on the ground before assembling their aboveground pools. Although sand is a recommended surface, it also has its disadvantages. Sand does not stop roots from growing up under a pool. Furthermore, over time, sand tends to become intermixed with the topsoil and obtains the properties of topsoil rather than that of granular sand. Another disadvantage of sand is that it is very heavy. Large above-ground pools may require thousands of pounds of sand to properly prepare the ground below the pool liner. It takes a great deal of time and labor to transport and spread that amount of sand. Lastly, sand flows. As such, sand cannot be used on wooden decks that have spaces between the planks, else the sand will flow through the spaces between the planks. Accordingly, sand cannot be used under small children's pools that are often placed on decks or wooden patios.
A need therefore exists for a new device that can be placed under a pool liner that replaces the use of sand but does not have the disadvantages of sand. This need is met by the present invention as described and claimed below.